It is known to use Laser Weld Deposition techniques to build structures on a substrate. In some circumstances deposition is required along the edge of a component, such as a rotor blade from turbo machinery in order to repair damage or wear to the tip or edge of the blade. Commonly the blade is ground back to remove the damaged area and laser weld deposition is used to join material to the blade to build a structure which can be machined to form a required blade geometry. FIG. 1 shows a component 10 with material 12 being deposited on its tip 14 by a laser weld deposition technique. Powder 16 of a suitable material is directed towards the tip 14 from a nozzle 18, and enters the path of a laser beam centroid and perimeter 20 from a laser 22 which briefly brings it and the surface of the tip 14 to a molten state before solidifying and raising the overall height of the component 10. The laser 22 is moved backward and forward across the tip 14 to build the required structure, with the beam 20 being maintained substantially perpendicular to the surface of the tip 14 to ensure the energy density is evenly distributed where the beam 20 is incident upon the tip 14. In FIG. 1 the laser beam 20 is presented as single line, but in reality will have width and converge to a point to form a working area. Unless the position of the beam 20 is controlled very precisely, when the laser 18 reaches the edge 24 of the tip 14, a proportion of the beam energy may extend down a side 26 of the component 10, possibly heating the surface of the side 26 and changing the structure of the surface and/or causing stray powder 28 to become adhered to the side 26 of the blade 10. Extra machining operations may be required to repair damage caused or remove erroneously deposited material powder 28, which increases the overall component 10 manufacture time and cost.
Hence a method of depositing material at the edge of a substrate which reduces the likelihood of rework to the side of the substrate is highly desirable.